1. Field of the Invention
This invention relates to a photovoltaic device and a manufacturing method thereof. More specifically, the invention relates to a photovoltaic device including a substantially intrinsic second amorphous silicon layer located between crystalline silicon and a first amorphous silicon layer.
2. Description of Related Art
A photovoltaic device with the following structure has heretofore been known. Specifically, the photovoltaic device includes a substantially intrinsic second amorphous silicon layer (an i-type amorphous silicon layer) located between crystalline silicon (an n-type single-crystal silicon substrate) and a first amorphous silicon layer (a p-type amorphous silicon layer). Such photovoltaic device is disclosed in, for example, Japanese Patent Application Publication No. 2003-258287 (hereinafter referred to as “Patent Document 1”).
A photovoltaic device including a substantially intrinsic second amorphous silicon layer (an i-type amorphous silicon layer) located between crystalline silicon (an n-type single-crystal silicon substrate) and a first amorphous silicon layer (a p-type amorphous silicon layer) has heretofore been known as disclosed in, for example, Japanese Patent Application Publication No. 2003-258287 (hereinafter referred to as “Patent Document 1”).
Patent Document 1 discloses a photovoltaic device has an increased oxygen concentration in the vicinity of the interface between an i-type amorphous silicon layer and an n-type single-crystal silicon substrate. By employing this configuration, defect density at the interface between the i-type amorphous silicon layer and the n-type single-crystal silicon substrate is reduced and occurrence of carrier recombination is thereby suppressed. In this way, Patent Document 1 achieves improvement in output characteristics of the photovoltaic device.